Minimizing underestimation rate of microcalcifications excised via vacuum-assisted breast biopsy: a blind study

PURPOSE: The main disadvantage of Vacuum Assisted Breast Biopsy (VABB) is the probability of underestimating atypical ductal hyperplasia (ADH) and ductal carcinoma in situ (DCIS). This study evaluates a modified way of performing VABB. METHODS: 266 women with microcalcifications graded BI-RADS 3&4 underwent VABB (11G) on the Fischer's table. 133 women were allocated to the "standard" protocol and 24 cores were obtained (1 offset-main target and one additional offset). 133 women were randomly allocated to the "extended" protocol and 96 cores were excised (one offset- main target and 7 peripheral offsets). A preoperative diagnosis was established, and the removed volume was calculated. When precursor or malignant lesions were diagnosed, open surgery was performed. A second pathologist, blind to the preoperative results and to the protocol made the postoperative diagnosis. The discrepancy between preoperative and postoperative diagnoses was evaluated. RESULTS: When the standard protocol was applied, the underestimation rate for preoperative ADH, lobular neoplasia (LN), DCIS was 16.7%, 50% and 14.3% correspondingly. In the extended protocol, no underestimation was present in LN, ADH, but the underestimation rate for DCIS was 6.3%. In the extended protocol, no precursor/malignant tissue was left after VABB in all ADH cases, in 87.5% of LN cases, in 73.3% of DCIS, and in 50% of invasive carcinomas. The volume excised was 2.33 +/- 0.60 cc and 6.14 +/- 1.30 cc for the standard and the extended protocol, respectively. The rate of hematoma formation did not differ between the two protocols. CONCLUSIONS: This recently introduced, "extended" way of performing VABB in microcalcifications safely minimizes the underestimation rate, which may lead to a modified management of ADH lesions.